Rifles such as but not limited to M16's and AR-15's can be configured in both automatic and semi-automatic configurations wherein these types of rifles are capable of firing a high capacity of ammunition rounds in short time periods. A critical component to these types of firearms is what is commonly known as a bolt carrier assembly. A conventional bolt carrier assembly includes elements such as but not limited to a bolt carrier, a bolt, a firing pin and a cam pin. Bolt carriers are generally cylindrical in shape having a bore throughout its length and further includes an opening on the top and bottom so as to permit a hammer to extend into the interior of the bolt carrier and strike the firing pin. The exterior of the bolt carrier is typically configured with a plurality of lands that are raised portions of the surface of the bolt carrier and function to engage the interior surface of the upper receiver in order to provide alignment.
One problem with conventional bolt carriers is the conventional configuration of lands requires some degree of spacing tolerance in order to permit the bolt carrier to execute a reciprocating motion within the upper receiver. During use of the firearm the bolt carrier will reciprocate within the the upper receiver as subsequent rounds of ammunition are loaded and fired. As the bolt carrier reciprocates a portion thereof will extend into a buffer tube, which is a tube located in the stock of the gun having a hollow passage permitting the bolt carrier to travel the required distance. Alignment of the buffer tube with the upper receiver is critical. The combination of aforementioned space tolerances and vibrations that occur during firing of a round of ammunition can create a less than desirable action of the bolt carrier. In some cases the bolt carrier can improperly engage the interior surface of the buffer tube resulting in poor performance of the firearm.
Accordingly, there is a need for a bolt carrier that is configured to provide a reduced friction with the upper receiver and further provide improved alignment within the upper receiver and buffer tube.